656399 has 8 divisors (see below), whose sum is σ = 679728. Its totient is φ = 633600.

The previous prime is 656389. The next prime is 656407. The reversal of 656399 is 993656.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-656399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6449 + ... + 6549.

It is an arithmetic number, because the mean of its divisors is an integer number (84966).

2⁶⁵⁶³⁹⁹ is an apocalyptic number.

656399 is a deficient number, since it is larger than the sum of its proper divisors (23329).

656399 is a wasteful number, since it uses less digits than its factorization.

656399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265.

The product of its digits is 43740, while the sum is 38.

The square root of 656399 is about 810.1845468781. The cubic root of 656399 is about 86.9072424876.

The spelling of 656399 in words is "six hundred fifty-six thousand, three hundred ninety-nine".